Predicting Drag Coefficient of Pneumatic Capsule
Publication: Journal of Transportation Engineering
Volume 127, Issue 5
Abstract
This research compares various methods for determining the drag coefficient of a capsule moving through a pneumatic capsule pipeline. A theoretical drag coefficient equation is derived using the 1D energy equation, continuity equation, and momentum equation. The equation contains the orifice coefficients of the end disks, which cannot be predicted accurately without knowing the curvature of the edge of the end disks. The equation is compared with other equations and experimental data found in literature. Using the sharp-crested orifice coefficient published in textbooks overpredicts experimental data by >30%. Calibrating the equation to match individual sets of experimental data yields a maximum 14% error. Finally, using the equation and an empirical formula to correct the orifice coefficient as a function of the diameter ratio of the end disks can predict the drag coefficient within 20% of the experimental data. Achieving greater accuracy requires more accurate determination of the ratio of pipe to disk diameter, curvature of the disk edge, or direct measurement of the drag of individual capsules through model or prototype tests.
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References
1.
Bomba, J. G., ed. ( 1997). “Pipeline research needs.” Proc., Workshop on Pipeline Res. Needs, ASCE, New York.
2.
Carstens, M. R. ( 1970). “Analysis of a low-speed capsule-transport pipeline.” Proc., Hydrostransport 1, Paper C4, British Hydromechanics Research Association, Cranfield, Bedford, U.K., 73–88.
3.
Engineering Council. ( 1997). A vision for transport 2020, Institution of Civil Engineers, London, U.K.
4.
Gao, X. ( 1999). “Hydrodynamics of HCP with slopes and bends.” PhD dissertation, Dept. of Civ. Engrg., University of Missouri-Columbia, Columbia, Mo.
5.
Interdepartmental Underground Transport Task Force (IUTTF). ( 1998). Underground freight transport—A challenge for the future, Ministry of Transport, Public Works and Water Management, Den Haag, The Netherlands.
6.
Jvarsheishvili, A. G. ( 1981). “Pneumo-capsule pipelines in U.S.S.R.,” J. Pipelines, 1(1), 109–110.
7.
Kosugi, S. ( 1985). “A basic study on the design of the pneumatic capsule pipeline system.” PhD dissertation, Dept. of Mech. Engrg., Osaka, University, Osaka, Japan.
8.
Kosugi, S. ( 1992). “A capsule pipeline system for limestone transportation.” Proc., 7th Int. Symp. on Freight Pipelines, Institution of Engineers, Barton, Australia, 13–17.
9.
Kosugi, S. ( 1999). “Pneumatic capsule pipelines in Japan and future developments.” Proc., 1st Int. Symp. on Underground Freight Transport by Capsule Pipelines and Other Tube/Tunnel Sys., University of Missouri. Columbia, Columbia, Mo., 61–73.
10.
Liu, H. ( 1993). “Hydraulic behavior of coal log flow in pipe.” Freight pipelines, G. F. Round, ed., Elsevier Science Publishing Co., Inc., New York, 215–230.
11.
Liu, H., and Richards, J. (1994). “Hydraulics of stationary capsule in pipe.”J. Hydr. Engrg., ASCE, 120(1), 22–40.
12.
Morikawa, Y., Tsuji, Y., Chono, S., and Yoshida, H. ( 1984). “A fundamental investigation of the capsule transport.” Bull. JSME, 27(232), 2181–2187.
13.
National Science and Technology Council (NSTC). ( 1997). Transportation science and technology strategy, Comm. on Transp. Res. and Devel., Intermodal Transportation Science and Technology Strategy Team, Washington, D.C.
14.
Papanastasiou, T. ( 1994). Applied fluid mechanics, Prentice-Hall, Englewood Cliffs, N.J.
15.
Simper, J. I., and Baker, P. J. ( 1973). “Pneumatic pipeline capsule systems—The future potential.” Proc., Pneumotransport 2, Paper F4, British Hydromechanics Research Association, Cranfield, Bedford, U.K., 31–39.
16.
Task Committee on Freight Pipelines (TCFP). (1998). “Freight pipelines: Current status and anticipated future use.”J. Transp. Engrg., ASCE, 124(4), 300–310.
17.
Tsuji, Y., Morikawa, Y., and Seki, W. ( 1985). “Velocity control in a capsule pipeline by changing the area of the end-plate.” J. Pipelines, 5(2), 147–153.
18.
York, K. ( 1999). “Predicting the performance of a PCP system using linear induction motor for capsule propulsion.” MS thesis, Dept. of Civ. and Envir. Engrg., University of Missouri-Columbia, Columbia, Mo.
19.
Zandi, I., and Kim, K. ( 1974). “Solid pipeline conserves energy.” Transp. Res., 8, 471–480.
20.
Zhai, D. Q. ( 1995). “Computational analyses of capsule transport in pipe.” MS thesis, Dept. of Mech. and Aerospace Engrg., University of Missouri-Columbia, Columbia, Mo.
Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 127 • Issue 5 • October 2001
Pages: 390 - 397
History
Received: Oct 19, 1998
Published online: Oct 1, 2001
Published in print: Oct 2001
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